發(fā)布時間：2018-01-11 06:20

  本文關鍵詞：一步法合成Pt@ZIF-8及其在1,4-丁炔二醇選擇加氫中的應用（英文）　出處：《催化學報》2016年09期 　論文類型：期刊論文

  更多相關文章： 鉑溶膠 ZIF- 一步合成 -丁炔二醇 選擇加氫

【摘要】：1,4-丁炔二醇(BYD)部分加氫生成1,4-丁烯二醇(BED),BED進一步加氫生成1,4-丁二醇(BDO).此外,BYD,BED和BDO還會發(fā)生脫水反應生成單醇類產(chǎn)物.工業(yè)上BYD加氫反應主要用于生產(chǎn)BDO.由于傳統(tǒng)的單金屬加氫催化劑很難控制反應的加氫程度,因此一般通過提高反應溫度和壓力使BYD盡量轉化為完全加氫產(chǎn)物BDO,以減少部分加氫產(chǎn)物BED對最終產(chǎn)品收率的影響.部分加氫產(chǎn)物BED在精細化工領域也具有重要的應用,所以選擇合適的催化劑和反應條件來提高部分加氫產(chǎn)物BED的選擇性具有重要的理論意義和潛在應用價值.文獻中常采用Zn、微生物等活性抑制劑來降低貴金屬催化劑的加氫活性.這些方法往往比較復雜,所使用的添加劑不僅存在毒性和污染產(chǎn)物,還會增加成本.這些方法得到的催化材料雖然可以提高烯醇的選擇性,但是仍需要嚴格控制反應條件才能得到較高收率的部分加氫產(chǎn)物.本文基于MOFs材料獨特的結構和性質,探索了MOFs負載型貴金屬催化劑在選擇加氫反應中的催化性能.首先制備了一種羧酸根保護的Pt納米溶膠,并以水為溶劑,增加2-甲基咪唑的加入量,實現(xiàn)了室溫下ZIF-8晶體的快速生成.在室溫合成ZIF-8的過程中加入羧酸根保護的Pt納米溶膠,通過羧酸根與ZIF-8之間存在的化學吸附力,實現(xiàn)ZIF-8對Pt納米粒子的包覆.羧酸根不僅可以穩(wěn)定溶液中的納米粒子,同時還起著"橋梁"的作用.羧酸根中的C=O基團與ZIF-8中的Zn原子或有機骨架之間弱的配位作用,增加了納米粒子和ZIF-8之間的親和力,實現(xiàn)了金屬納米粒子被ZIF-8包圍.Pt納米粒子的引入對ZIF-8的形成也沒有影響,得到的Pt@ZIF-8材料擁有良好的晶體結構和高的比表面積.采用XRD、N2吸附和TEM等表征揭示了Pt@ZIF-8的結構特點,并研究了其在水相1,4-丁炔二醇加氫反應中的催化性能.結果顯示,該材料不僅具有很高的活性,還具有突出的部分加氫選擇性.在5次循環(huán)反應中,BYD轉化率沒有明顯變化,說明催化劑在反應過程中活性沒有降低.在多次反應之后,反應產(chǎn)物的分布也沒有發(fā)生明顯變化,1,4-丁烯二醇選擇性在5次反應中都保持在94%以上.結構表征結果則顯示,在4次循環(huán)使用之后,催化劑的結構已經(jīng)遭到破壞;5次循環(huán)使用之后,催化劑的XRD譜圖中ZIF-8的特征衍射峰完全消失.其余譜峰為Zn O特征衍射峰,說明由于反應溫度較高,催化劑在多次反應之后其載體ZIF-8發(fā)生了分解.循環(huán)壽命實驗說明,ZIF-8中Zn離子和含氮有機骨架的抑制作用是導致1,4-丁烯二醇高選擇性的重要原因.ZIF-8的分解雖然會使孔道塌陷,但是結構中的Zn和含氮的有機骨架組成依然存在,仍然可以達到抑制烯醇進一步加氫的效果,并且Pt納米溶膠主要存在于外表面,所以催化劑的活性和選擇性沒有發(fā)生明顯變化.
[Abstract]:1,4- butynediol (BYD) partially hydrogenated to 1,4- butylene glycol (BED), BED further hydrogenation of 1,4- butanediol (BDO). In addition, BYD, BED and BDO will generate the dehydration of alcohol products. Single industry BYD hydrogenation is mainly used for the production of BDO. due to hydrogenation degree of traditional single gold a hydrogenation catalyst is difficult to control the reaction, so by increasing the reaction temperature and pressure to make BYD into full hydrogenation products of BDO, in order to reduce the influence of partial hydrogenation of BED product to the final product yield. Partial hydrogenation products of BED in fine chemical industry also has important applications, so the choice of catalyst and reaction the appropriate condition has important theoretical significance and potential application value of selective partial hydrogenation products of BED to improve Zn. Often used in the literature, the hydrogenation activity of microbial inhibitors to reduce the activity of noble metal catalysts. These methods to Compared to the complex additives used not only the toxicity and pollution products, will increase the cost. Although the catalytic material obtained by these methods can improve the selectivity of alcohol, but still need to strictly control the reaction conditions to get partial hydrogenation products in high yield. This paper is based on the structure and properties of MOFs materials are unique, to explore the MOFs supported noble metal catalysts and catalytic performance in hydrogenation reactions in the first choice. Pt nano sol a carboxylate protection by taking water as solvent, increasing the amount of 2- methyl imidazole, realize the rapid generation of ZIF-8 crystal at room temperature. Pt nano sol adding carboxylate protection in process synthesis at room temperature in ZIF-8, by chemical adsorption force between the carboxyl group and ZIF-8, ZIF-8 of Pt nanoparticles coated with carboxylate. Nanoparticles in solution can not only stable, at the same time Play the role of bridge between C=O and ZIF-8 groups. The carboxylate Zn atoms in the organic framework or weak coordination effect, increase the affinity between nanoparticles and ZIF-8, the metal nanoparticles were introduced surrounded by ZIF-8.Pt nanoparticles on the formation of ZIF-8 did not affect the Pt@ZIF-8 material has good crystal structure and high specific surface area. By XRD, N2 adsorption and TEM characterization revealed the structural characteristics of Pt@ZIF-8, and the study of their catalytic properties in aqueous 1,4- butynediol hydrogenation reaction. The results showed that the material not only has high activity, but also has some prominent selective hydrogenation in 5 cycles of reaction, the conversion rate of BYD did not change significantly, indicating that the catalyst during the reaction activity does not decrease. In many reactions, the distribution of reaction products did not change significantly, 1,4- butylene glycol In the 5 reaction selectivity is maintained at more than 94%. The characterization results showed that after 4 cycles, the structure of the catalysts has been destroyed; after 5 cycles, the characteristic diffraction peaks in the XRD spectra of the catalysts of ZIF-8 disappeared. The other peak is Zn O characteristic diffraction peaks, indicating that due to high reaction temperature, catalyst in the reaction times after the carrier ZIF-8 decomposes. The cycle life test, the inhibition effect of Zn ion and nitrogen containing organic framework in ZIF-8 is to make the pore collapse although an important reason for.ZIF-8 decomposition 1,4- butylene glycol selectivity, but the structure of the Zn and nitrogen-containing organic framework which still exists, still can inhibit the further hydrogenation of enol effect, and mainly on the outer surface of Pt nano sol, so the activity and selectivity of the catalyst did not change significantly.

【作者單位】： 大連理工大學化工學院先進材料和催化工程實驗室;愛荷華州立大學生物質可再生能源實驗室;
【基金】：supported by the National Natural Science Foundation of China(21573031 and 21428301) the Fundamental Research Funds for the Central Universities(DUT15ZD106 and DUT15RC(4)09)~~
【分類號】：O643.36
【正文快照】： 1.Introduction The selective hydrogenation of carbon-carbon triple bonds to double bonds is an important process in the fine chemicals industry,and is relevant to commodities and other specialty chemicals production[1,2].The partial hydrogenation of1,4-

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